The problem with a grind game is that people inevitably realize that grinding is stupid. Literally, you don't have time for that shit. Getting to 30 in itself would require easily a week of hardcore grinding, 70 would take months depending on the class, and 120 would require a year of grinding for even the most dedicated of players.
Literally, killing the optimal mob for grinding at 30-40 would build less than 0.01% of the xp needed to level. It would take over 10,000 mobs killed for one goddamn level. Competing with other players grinding the exact same mob. With fractional xp share for dealing damage. Which you won't do if a higher level player is aoe spamming to farm a specific drop. Which they always were doing.
This game literally is the pinnacle example of a grind.